PURPOSE: To shorten the time required for washing by bringing the outer surface of a cylinder body into contact with all outer surfaces of many wafers which are held with a carrier, rotating and driving the cylinder body with a driving means, and rotating many wafers.

CONSTITUTION: In a carrier 11, many wafers 10 in a vertical attitude are mounted so that a specified interval is provided in the direction of the thickness and the wafers can be rotated in the circumferential direction under the state wherein the wafers 10 are arranged in one line. Pure water flows from the lower side to the upper side under the state wherein the carrier is provided in a water washing chamber 20. The carrier 11 is mounted on a porous plate 4 in the striding state on a cylinder body 6. The outer surface of the cylinder body 6 is in contact with all outer surfaces of many wafers 10 which are mounted on the carrier 11. The cylinder body 6 is rotated with the rotation of a motor. Since the wafers 10 are rotated, the parts of the wafers in contact with the carrier 11 and the parts in the vicinity of the contact points are not fixed to one place, but the positions are changed. As a result, the pure water can be made to flow uniformly on the surfaces of the wafers 10. The washing of the specified place of each wafer 10 is not delayed. The entire surface of each wafer 10 can be washed at an approximately uniform speed.